Question

A(2,-1) B(1,2) ecuatia dreptei AB in 2 moduri

Answer 1

Metoda I:
(x-2)/(1-2) = (y- -1)/(2+1)
(x-2)/(-1) = (y+1)/3
-3(x-2)=y+1
-3x-y+5=0 ⇔ y= -3x+5
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Sau prin determinant

Metoda2:

Ix  y  1I
I2 -1 1I = x(-1-2) -y(2-1)+1(4+1)[dezvoltare dupa elementele primei linii]
I1  2  1I                                               
⇒ -3x-y+5=0 ⇔ y = -3x+5
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